A circuit is a closed loop that electrons can travel in. A source of electricity, such as a battery, provides electrical energy in the circuit. Generally, there is some appliance that uses electricity in the circuit. The appliance may, for example, provide light or heat or mechanical energy.
The culture might not be stained properly or the culture might be too old.
Explanation:
Gram staining is done to differentiate between gram-positive and gram-negative bacteria according to the difference in their cell wall. In gram staining, the gram-positive bacteria appears violet and gram-negative bacteria appear pink in color.
Therefore if a pure culture contains have both red and purple cocci that it can be concluded that the gram stating was not done properly like too much destaining was done or too much safranin was used or maybe the culture is too old so that cell wall of some bacteria degrades.
